In the cutting of gears and other toothed articles, such as bevel gears and in particular spiral bevel and hypoid gears, it is common to produce a burr at the end of a tooth where the cutting tool exits the tooth slot. Burrs are particularly noted at the end of concave tooth flanks on spiral bevel ring gears and pinions. Regardless of location on a gear, burrs pose a safety and performance hazard and therefore must be removed.
It may also be desirable to provide a chamfer at one or both ends of gear teeth including tip and root ends. After cutting, sharp corners usually exist at the intersection of the tooth sides, tip and/or root with the front and/or back faces and removing the sharp corners makes handling the gear safer and eliminates a potential area of unacceptably high hardness after heat treating.
Chamfering may be carried out at various times and locations with respect to the actual cutting process. Separate chamfering machines are known in the art. Chamfering and/or deburring of a gear with a rotary tool while the gear remains positioned on the work spindle of a cutting machine is known, for example, from U.S. Pat. No. 7,431,544 or U.S. Patent Application Publication No. 2007/0020058. However, chamfering in this manner slows production of the particular machine since cutting of a subsequent workpiece must wait until after the gear is chamfered and/or deburred.
From U.S. Pat. No. 3,083,616 it is disclosed to provide a chamfering mechanism adjacent a workpiece spindle in a gear cutting machine whereby chamfering takes place simultaneously with gear cutting. A rod-shaped deburring tool advances from a retracted position to chamfer the edge of a newly-cut tooth as the gear is indexed to the next tooth slot position for cutting. While such an arrangement may reduce non-cutting time on the machine, there is little flexibility with such a system with respect to modifying the size, extent or shape of the chamfer. Furthermore, the disclosed chamfering mechanism is not capable of chamfering gears produced by continuous indexing processes (i.e. face hobbing).